It is probably not a current model, which is why is is not on their website, but you can figure it out.

1) The BTU input is printed on a spec label on the water heater.
2) The first hour delivery can be approximated as follows: Add 70% of the gallon capacity ( = 52 gallons) to the recovery rate which you can use 1 gallon per hour per thousand BTU.

For example, if it was a 60,000 BTU unit, we would add 52 to 60 , givig an approximate FIRST hour of 112 gallons. Important to note that the SECOND and subsequent hours would be 60 gallons per hour.